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PowerPoint presentation on Cellular Respiration and processes used to create ATP
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Cellular Respiration How the body gets it’s energy
What is Cellular Respiration? • Cellular Respiration is the set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.
Adenosine Triphosphate(ATP) • ATP is the basic energy unit of the cell. • The molecule itself consist of one adenine base with 3 phosphates attached. • Energy from the molecule is stored within the the phosphate bonds. • When a phosphate is cleaved energy is released. • ATP is required for many of our body’s physiological processes to maintain homeostasis
How do we get ATP? • Carbohydrates are key in the production of ATP • The main carb that is broken down for cellular respiration is Glucose • Glucose then undergoes a series of metabolic reactions to gain a maximum number of ATPs
Glucose • Glucose is the simplest form of sugar and a carbohydrate • It consists of 6 carbons
Glycolysis cont.… • Glycolysis is an anaerobic reaction, meaning that is can occur without the presence of oxygen, that takes place in the cytoplasm • This process takes the 6 carbon glucose molecule and breaks it down into two 3 carbon pyruvates molecules. • For the process to start an initial investment of 2 ATP is required • From the glucose molecule, a 6 carbon intermediate is formed. Next 2 compounds of PGAL(phosphoglyceraldehyde) are formed along with 2 hydrogensjoining NAD to form NADH+. • Finally two molecules of pyruvic acid are formed along with the production of 4 ATP (2 net). • If no oxygen is present after glycolysis, the pyruvate will turn to lactate and undergo lactic acid fermentation.
Kreb’s cont.… • The pyruvate molecules from glycolysis with the presence of oxygen will enter the Kreb’s Cycle. • Coenzyme A will join the pyruvates to form Acetyl CoA. The acetyl CoA join oxaloacetate to make a 6 carbon citric acid compound. • The citric acid compound will cleave two carbons and allow for the production of 3 NADH’s, 1 molecule of ATP, and 1 FADH2. Ultimately oxaloacetate will be formed and join the other acetyl CoA molecule and repeat the process. • Remember that there are two pyruvates created from glycolysis so that means there will be two Acetyl CoA’s and two turn of the Kreb’s Cycle. • Outputs are : 6 molecules of NADH, 2 molecules of FADH2, and 2 molecules of ATP.
ETC cont.…. • The ETC is the final process in cellular respiration. • Along with the Kreb’s cycle the ETC is also aerobic and takes place within the mitochondria. • Within the chain, there are four protein complexes known as cytochromes in which electrons will be passed along. • Now NADH and FADH2 become big players and are used to donate electrons. These molecules are oxidized and reduced as they travel down the chain. • As NADH and FADH2 are dropping of electrons, it is causing a Hydrogen gradient in the inter-membrane space and the matrix. This gradient is important because it forces the excess Hydrogen molecules through the ATP Synthase pump to generate ATP. • Any excess Hydrogen molecules will be accepted by Oxygen to form a by product of water
Aerobic vs. Anaerobic • Aerobic • Krebs cycle • ETC • Requires oxygen • Takes place in mitochondria • More ATP produced • Longer energy • Slow twitch • Anaerobic • Glycolysis • Takes place in cytosol/cytoplasm • No oxygen required • Not a lot of ATP produced • Fast twitch • Fatigue quickly • Resorts to lactic acid fermentation
ATP Totals • Glycolysis: 4 ATP (2 net) • Kreb’s : 2 ATP • ETC: 32 ATP • So in the end we can see that one glucose molecule can lead to the production of around 36 ATP units.
Questions? • Why do we need energy? • What are carbohydrates? • What is the most easily accessible carbohydrate? • What are the three major components of cellular respiration? • What process would your body rely on if you were walking to your locker? House? • What happens after glycolysis if oxygen is present? No oxygen present? • What is the final electron acceptor? • Compare and contrast Aerobic and Anaerobic pathways. • About how many ATP units can come from a single glucose molecule? • Which process is the most efficient and why?